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过滤筛选
- 2018
- electromagnetic pulse
- cell proliferation
- cell membrane permeability
- cell response to electromagnetic stress
- apoptosis
- cancer therapy
- necrosis
- Intelligent Medical Engineering
- V.N. Karazin Kharkiv National University
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Stomatal response to blue light in crassulacean acid metabolism plants <i>Kalanchoe pinnata</i> and <i>Kalanchoe daigremontiana</i>
摘要： Blue light (BL) is a fundamental cue for stomatal opening in both C3 and C4 plants. However, it is unknown whether crassulacean acid metabolism (CAM) plants open their stomata in response to BL. We investigated stomatal BL responses in the obligate CAM plants Kalanchoe pinnata and Kalanchoe daigremontiana that characteristically open their stomata at night and close them for part of the day, as contrasted with C3 and C4 plants. Stomata opened in response to weak BL superimposed on background red light in both intact leaves and detached epidermal peels of K. pinnata and K. daigremontiana. BL-dependent stomatal opening was completely inhibited by tautomycin and vanadate, which repress type 1 protein phosphatase and plasma membrane H+-ATPase, respectively. The plasma membrane H+-ATPase activator fusicoccin (FC) induced stomatal opening in the dark. Both BL and FC induced phosphorylation of the guard cell plasma membrane H+-ATPase in K. pinnata. These results indicate that BL-dependent stomatal opening occurs in the obligate CAM plants K. pinnata and K. daigremontiana independently of photosynthetic CO2 assimilation mode.
关键词： phototropins,CAM plants,plasma membrane H+-ATPase,stomatal opening,blue light,signal transduction
更新于2025-09-23 15:23:52
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Tilted Fiber Bragg Grating Sensor Using Chemical Plating of a Palladium Membrane for the Detection of Hydrogen Leakage
摘要： A tilted ?ber Bragg grating (TFBG) hydrogen sensor coated with a palladium (Pd) membrane by the electroless plating method is proposed in this paper. A uniform layer of Pd metal is fabricated in aqueous solutions by the chemical coating method, which is used as the sensitive element to detect the change of the surrounding refractive index (SRI) caused by hydrogen absorption. The change in SRI causes an unsynchronized change of the cladding modes and the Bragg peak in the TFBG transmission spectrum, thereby eliminating the cross-sensitivity due to membrane expansion and is able to simultaneously monitor the presence of cracks in the pipe, as well as the hydrogen leakage. By subtracting the wavelength shift caused by ?ber expansion, the change of SRI, i.e., the information from the H2 level, can be separately obtained. The drifted wavelength is measured for the H2 concentration below the hydrogen explosion limit between 1% and 4%. The chemical-based coating has the advantages of a low cost, a simple operation, and being suitable for coating on long ?ber structures. The proposed sensor is able to detect the H2 signal in 5 min at a 1% H2 concentration. The proposed sensor is proved to be able to monitor the hydrogen level without the cross-sensitivity of temperature variation and expansion strains, so could be a good candidate for security applications in industry.
关键词： electroless plating,tilted ?ber Bragg grating,optical ?ber hydrogen sensor,palladium membrane
更新于2025-09-23 15:22:29
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Silica aerogel membranes fabricated using removable nitrocellulose scaffolds
摘要： Two different methods were developed to generate silica-based aerogel membranes using nitrocellulose scaffolds. The first method involved incorporating fibers of nitrocellulose (NC) into the sol prior to gelation. NC fibers were either removed using a solvent during aging or calcining after aerogel formation to produce reticulated micron-sized channels in the aerogels. In the second method, an NC lacquer was mixed with the sol, and the mixture separated into a NC-rich phase and a sol-rich phase. The NC phase was subsequently removed from the aerogel using a solvent, creating aerogels with interconnected porosity. Aerogels were prepared from tetraethyloxysilane (TEOS) as a precursor and methyltriethoxysilane (MTES) as a co-precursor. Replacing TEOS with 25 vol% MTES increased the mechanical stability, allowing for greater ease of handling. Additionally, the more open network of the MTES gels led to higher helium gas permeability than that for the pure TEOS gels.
关键词： Silica membrane,Interconnected porosity,Nitrocellulose template,Cellulose nitrate,Silica aerogel
更新于2025-09-23 15:22:29
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A genetically encoded FRET biosensor for visualizing EphA4 activity in different compartments of the plasma membrane
摘要： The EphA4 receptor tyrosine kinase is well known for its pivotal role in development, cancer progression, and neurological disorders. However, how EphA4 kinase activity is regulated in time and space still remains unclear. To visualize EphA4 activity in different membrane microdomains, we developed a sensitive EphA4 biosensor based on F?rster resonance energy transfer (FRET), and targeted it in or outside raft-like microdomains in the plasma membrane. We showed that our biosensor can produce a robust and specific FRET response upon EphA4 activation, both in vitro and in live cells. Interestingly, we observed stronger FRET responses for the non-raft targeting biosensor than for the raft targeting biosensor, suggesting that stronger EphA4 activation may occur in non-raft regions. Further investigations revealed the importance of the actin cytoskeleton in suppressing EphA4 activity in raft-like microdomains. Therefore, our FRET-based EphA4 biosensor could serve as a powerful tool to visualize and investigate EphA4 activation and signaling in specific subcellular compartments of single live cells.
关键词： EphA4,Membrane microdomain,cytoskeleton,FRET biosensor,Live cell imaging
更新于2025-09-23 15:22:29
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Increased resistance of <i>Salmonella</i> Typhimurium and <i>Escherichia coli</i> O157:H7 to 222-nm krypton-chlorine excilamp treatment by acid adaptation
摘要： In this study, we examined the change in resistance of Salmonella Typhimurium and Escherichia coli O157:H7 to 222-nm krypton-chlorine (KrCl) excilamp treatment as influenced by acid adaptation, and identified a mechanism of resistance change. In addition, changes in apple juice quality indicators such as color, total phenols and DPPH free radical scavenging activity during treatment were measured. Acid adapted- and non-acid adapted pathogens were induced by growing the cells in TSB without dextrose (TSB w/o D) at pH 7.3 and TSB w/o D at pH 5.0 adjusted with HCl, respectively. For the KrCl excilamp treatment, acid-adapted pathogens exhibited significantly (P < 0.05) higher D5d values, which indicate dosages required for achieving 5-log reduction, than non-acid adapted pathogens in both commercially clarified apple juice and PBS, and the pathogens in the juice showed significantly (P < 0.05) higher D5d values than those in PBS because of the UV-absorbing characteristics of apple juice. Through mechanism identification, it was found that the generation of lipid peroxidation in cell membrane, inducing cell membrane destruction, of acid adapted cells was significantly (P < 0.05) less than that of non-acid adapted cells for the same amount of reactive oxygen species (ROS) generated at the same dose because the ratio of unsaturated to saturated fatty acids (USFA/SFA) in the cell membrane was significantly (P < 0.05) decreased as a result of acid adaptation. Treated apple juice showed no significant (P > 0.05) differences in quality indicators compared to untreated controls during the treatment of 1773 mJ/cm2.
关键词： acid adaptation,ROS,E. coli O157:H7,apple juice,cell membrane fatty acid,ultraviolet irradiation,S. Typhimurium,222-nm KrCl excilamp
更新于2025-09-23 15:22:29
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A chemogenetic approach for optical monitoring of voltage in neurons
摘要： Optical monitoring of neuronal voltage using fluorescent indicators is a powerful approach for interrogation of the cellular and molecular logic of the nervous system. Here we describe a Semisynthetic Tethered Voltage Indicator (STeVI1) based upon Nile Red that displays voltage sensitivity when genetically targeted to neuronal membranes. This environmentally sensitive probe allows for wash-free imaging and faithfully detects supra- and subthreshold activity in neurons.
关键词： membrane potential probes,voltage imaging,genetic targeting,protein tags,fluorogenic probes
更新于2025-09-23 15:22:29
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The correlation between visual acuity outcomes and optical coherence tomography parameters following surgery for diabetic epiretinal membrane and taut posterior hyaloid
摘要： Purpose: To evaluate the relationship between visual outcomes and the determinants detected by spectral domain optical coherence tomography (OCT) in eyes with epiretinal membrane (ERM) and/or taut posterior hyaloid (TPH) that underwent pars plana vitrectomy (PPV). Materials and methods: A total of 30 participants with diabetic ERM and TPH were included in the study. All study participants underwent PPV. Preoperative and postoperative best corrected visual acuity (BCVA), peripapillary retinal nerve fiber layer (RNFL), macular RNFL, ganglion cell layer, inner plexiform layer, and ganglion cell complex thicknesses were measured in each participant. Linear regression analyses were performed to determine the association between the OCT parameters and the visual acuity measured at the time of the OCT measurement. Results: The postoperative BCVA logarithm of the minimum angle of resolution (logMAR) values were statistically higher than the preoperative values in the ERM group and TPH group (P=0.001 and P<0.001, respectively). The postoperative BCVA logMAR value was negatively correlated with average RNFL, inferior RNFL thicknesses, and image quality (P=0.002, P=0.004, and P=0.006, respectively). The preoperative and postoperative BCVA logMAR value difference was not correlated with age and all of the OCT parameters measured (P>0.05). Conclusion: This study shows that achievement of better peripapillary RNFL thickness results in better visual outcome after PPV and ERM/TPH removal.
关键词： retinal nerve fiber layer,ganglion cell complex,optical coherence tomography,taut posterior hyaloid,diabetic epiretinal membrane
更新于2025-09-23 15:22:29
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Mathematical modeling on non-dispersive extraction of germanium from aqueous solutions using Aliquat 336
摘要： In this work, the mathematical modeling of the facilitated transport of germanium (non-dispersive extraction) through a flat sheet membrane with an Aliquat 336 carrier was described. The flat sheet supported liquid membrane (FSSLM) experiments were performed under the condition being Ge ≈ 100 mg/L, the tartaric acid concentration of 2.76 mmol/L, and carrier concentrations of 2.5 to 10%v/v. The extraction equilibrium, mass transfer and diffusion equations based on Fick’s law were used. Modeling was carried out by programming in Matlab mathematical software to obtain the extraction (Kex) and mass transfer constants (Km) as the objective parameters. According to the model resolution, Kex and Km were found to be 0.178 and 9.25 × 10?2 cm/s, respectively. The correlation coefficients between model and experimental data relating to the Aliquat 336 concentrations of 2.5, 5, 7.5, and 10%v/v were found as 0.96, 0.98, 0.99, and 0.92. The parameters of root mean square (RMSE), bias, and scatter index (SI) showed the model accuracy. In addition, diffusion coefficients (Dm) relating to Aliquat 336 concentrations of 2.5, 5, 7.5, and 10%v/v were calculated using mass transfer coefficients to be 2.4 × 10??, 2.23 × 10??, 1.91 × 10??, and 1.79 × 10?? cm2/s, respectively.
关键词： supported liquid membrane,Aliquat 336,modeling,germanium,mass transfer
更新于2025-09-23 15:22:29
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Changes of Intracellular Porphyrin, Reactive Oxygen Species, and Fatty Acids Profiles During Inactivation of Methicillin-Resistant Staphylococcus aureus by Antimicrobial Blue Light
摘要： Antimicrobial blue light (aBL) has attracted increasing interest for its antimicrobial properties. However, the underlying bactericidal mechanism has not yet been verified. One hypothesis is that aBL causes the excitation of intracellular chromophores; leading to the generation of reactive oxygen species (ROS) and the resultant oxidization of various biomolecules. Thus, monitoring the levels of redox-sensitive intracellular biomolecules such as coproporphyrins, as well as singlet oxygen and various ROS may help to uncover the physiological changes induced by aBL and aid in establishing the underlying mechanism of action. Furthermore, the identification of novel targets of ROS, such as fatty acids, is of potential significance from a therapeutic perspective. In this study, we sought to investigate the molecular impact of aBL treatment on methicillin-resistant Staphylococcus aureus (MRSA). The results showed that aBL (5–80 J/cm2) exhibited a bactericidal effect on MRSA, and almost no bacteria survived when 80 J/cm2 had been delivered. Further studies revealed that the concentrations of certain intracellular molecules varied in response to aBL irradiation. Coproporphyrin levels were found to decrease gradually, while ROS levels increased rapidly. Moreover, imaging revealed the emergence and increase of singlet oxygen molecules. Concomitantly, the lipid peroxidation product malondialdehyde (MDA) increased in abundance and intracellular K+ leakage was observed, indicating permeability of the cell membrane. Atomic force microscopy showed that the cell surface exhibited a coarse appearance. Finally, fatty acid profiles at different illumination levels were monitored by GC-MS. The relative amounts of three unsaturated fatty acids (C16:1, C20:1, and C20:4) were decreased in response to aBL irradiation, which likely played a key role in the aforementioned membrane injuries. Collectively, these data suggest that the cell membrane is a major target of ROS during aBL irradiation, causing alterations to membrane lipid profiles, and in particular to the unsaturated fatty acid component.
关键词： membrane injuries,coproporphyrin,lipids,methicillin-resistant Staphylococcus aureus,antimicrobial blue light,unsaturated fatty acids
更新于2025-09-23 15:22:29
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Spectral versus Time-Domain OCT in Detecting Preoperative Epiretinal Membranes that Accompany Macular Holes
摘要： Purpose: To compare the sensitivities of spectral-domain optical coherence tomography (SD-OCT) versus time-domain OCT (TD-OCT) in identifying epiretinal membranes (ERM) preoperatively in patients who underwent surgery for full-thickness macular holes (FTMH). Methods: This is an interventional retrospective case series of 59 eyes diagnosed with FTMHs who underwent 25-G pars plana vitrectomy with internal limiting membrane peeling between 2009 and 2015. Preoperative OCTs were obtained by SD-OCT (Spectralis, Heidelberg, Germany) or TD-OCT (Stratus, Carl Zeiss Meditec, Dublin, CA, USA). Volume scans were reviewed for ERM accompanying the FTMH. This was compared to indocyanine green-negative staining and intraoperative findings of ERM as the gold standard. Results: Baseline characteristics between the SD-OCT and TD-OCT groups were comparable. Mean duration of postoperative follow-up was 41.4 weeks (±49.0). Of 59 eyes, 33 (55.9%) exhibited an ERM intraoperatively. Four ERMs (SD-OCT group) compared to 12 (TD-OCT group) were not visualized on preoperative OCT (p = 0.003). Sensitivity and specificity of SD-OCT in ERM detection was 79% and 100% compared to 14% and 91% for TD-OCT. Visual acuity improved in both arms (0.5 and 0.3 logMAR units in SD-OCT and TD-OCT, respectively (p = 0.002, 0.0002). Conclusions: We found that SD-OCT was superior to TD-OCT in identifying the presence of ERM preoperatively in patients who underwent macular hole surgery. Since ERMs may decrease the chance of successful pharmacologic vitreolysis, we recommend using SD-OCT over TD-OCT in the evaluation of patients with FTMH to more accurately identify ERMs and allow more comprehensive treatment decisions (pharmacologic versus surgical).
关键词： Epiretinal membrane,Spectral-domain optical coherence tomography,Macular hole,Time-domain optical coherence tomography
更新于2025-09-23 15:22:29